Preheat your gas or charcoal grill to reach a moderate heat of around 400 F.
For each packet of nacho goodeness, tear off a 2-foot length of heavy duty aluminum foil. Slightly pinch the sides to form a makeshift tray.
Pour tortilla chips across half of your foil, ensuring you leave a border for sealing later.
Sprinkle roughly 1/2 cup of pepper jack shreds and a 1/4 cup of cheddar over the chips.
Gently fold the foil to cover the layered chips, pinching the edges to seal the packet.
Position the foil packet on the grill rack and shut the lid, allowing it to cook for approximately 5 minutes. The cheese should melt, and the chip edges should get toasty. (Open the packet cautiously; hot steam might gush out.)
Open the packets carefully to avoid hot steam. Top the nachos with your favorite fixings and serve immediately with chilled Rombauer Sauvignon Blanc.